2009). Given that unipolar depression is becoming more prevalent (Song et al. 2008; Gonzalez et al. 2010), it is this website timely and especially important to understand the influence of depressed moods on social functioning, especially social decision making. One way to understand social decision making in people with depression is to have them complete tasks that involve cooperation, deception, decisions about risk, and behavior adjustment according to the responses of others. One task that suits these requirements

is the trust and reciprocity task first developed by McCabe and colleagues (2001), which we adapted Inhibitors,research,lifescience,medical for use in this study. The experimental task of the trust game required each participant Inhibitors,research,lifescience,medical (all women) to play the role of a trustee who received an investment from another player (the investor, also a woman [in this study a computer program]). As the investment profited, the trustee was requested by the investor to return a certain portion of the profit to her. Since the investor had no knowledge of the amount of profit, the trustee could decide whether she would return more than (defined as altruistic behavior), equal to (defined as honest behavior), or less than (defined as deceptive behavior) the requested amount. Navigating the trust and reciprocity task requires decision

Inhibitors,research,lifescience,medical making to balance risk and reward. But people with depression are less sensitive to the value of rewards and losses (Lerner et al. 2004; Pizzagalli et al. 2008), and this decreased sensitivity may influence their decision making. Indeed, numerous studies have shown that Inhibitors,research,lifescience,medical depressed patients fail to maximize the reward value of outcomes in serial decision tasks, seeming to lack the motivation to seek pleasurable stimuli (Lerner et al. 2004; Pizzagalli et al. 2008). Researchers have proposed that this Inhibitors,research,lifescience,medical reduced reactivity stems from anhedonia (Henriques and Davidson 2000; Lerner et al. 2004; Pizzagalli

et al. 2008). Other studies have proposed a biological explanation for this reduced reactivity, attributing it to dysfunction in the frontocingulate, thereby causing increased cognitive conflict (Knutson et al. 2008; Pizzagalli 2011). Depressed moods are also related to risk aversion and difficulty making decisions (Must et al. 2006; Nenkov et al. 2008; Smoski et al. 2008; Cella et al. 2010). There are reasons to believe as well that depression also affects Dipeptidyl peptidase altruism and cooperation. Although people with depression report feeling higher levels of guilt and empathic distress (O’Connor et al. 2002), they have weaker intention or ability to help others (O’Connor et al. 2007). To examine the relationship between depression and social decision making, we tested the behavior of depressed participants in the task game in this study. Because depression is linked with a low intention of helping others as well as low maximizing of benefits to oneself, we hypothesized that people in depressed moods would show less altruistic or deceptive behaviors than people in neutral moods.